Halo 3 Mythic Skulls Xbox 360

Halo 3 Mythic Skulls.
Each of the following skulls is available by having the mythic map packs and 
going into forge mode. Each skull has 25 gamerscore. Collect all 6 skulls to 
get a grand total of 175 gamerscore.

Assembly- This is the easiest skull to get. Enter forge mode and fly to the 
center tower. on one of the inside spires there is a skull. Land in spartan/ 
elite form onto the spire and press the appropriate button.

Orbital- Fly, or walk to the elevator system. There is a lookout covered by 
glass next to it. The skull rests on a few ledges above this. Fly to it and 
when you land, (closer to the elevator is best,) crouch and waddle over tothe 
skull and pick it up.

Heretic- Fly up to the center platform in the highest part of heretic. Fly 
around the room untill you can see the skull on a window-like sill  next to a 
beam. Turn back from moniter mode, as you fall, grab the skull.

Longshore- Fly to the water. From there continue along the coast untill you 
reach a wall with a sign for a whale on it. The skull is on the pipes nearest 
the water. Once you found the ledge, fall and grab the skull, you will either 
die, or turn into moniter mode, either way, you still get the achievement.

Citadel- Go to the blue side. Along the ceiling, there are some rafter 
connecting columns. In one of the rafters, there is a skull. I'd suggest 
marking it with something. You can use a grave lift and grenade to get it down. 
Or try to grab as you fall. If the grav lift deletes the skull, then just start 
a new round.

Sand Box- Go to the blue or red base and enter forge mode. Put down the four 
mines that you can, set respawn time for 10 seconds. Then hit x and make 
minnimum 4 and maxium 4. Exit forge mode and start tossing mine on the ground 
beneath you. After a while the blocks you are standing on will dissapear. fly 
towards the sunset. The Gaurdians won't shoot if done right. after reaching the 
end turn right and continue until you see the skull.

Brainpan: 25g